German Patent Application No. 35 19 611 describes gaseous-discharge lamps or high-pressure discharge lamps. The ballast unit required to supply the lamps with the necessary ignition voltage and maintaining voltage is arranged in a shaped housing, which is configured on the rear part of the reflector of the motor vehicle's headlamp unit. This housing increases the overall depth of the motor vehicle's headlamp unit, it being necessary for the high-voltage conducting lines to be run from the shaped housing to the lamp's burner vessel. This entails insulation problems and line losses.
European Patent No. 150 799 describes a low-pressure gaseous-discharge lamp, in which the ballast unit is arranged at the lamp base. However, such a low-pressure gaseous-discharge lamp is not suited for motor-vehicle headlamps, and the problems associated with electrode bushings arranged at opposite end regions, in conjunction with a ballast unit configured in the lamp base, are neither addressed nor solved by this publication.